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    <html lang="zh-CN">
    <head>
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      <title>大规模文件存储优化 - 交互式测验</title>
      <style>
        @import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;700&display=swap');
        
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          padding: 20px;
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        .quiz-header {
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          color: white;
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        .quiz-header h1 {
          margin: 0;
          font-size: 24px;
          font-weight: 700;
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        .quiz-header p {
            margin: 5px 0 0;
            font-size: 14px;
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        .quiz-body {
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        .progress-bar {
            display: none; /* 隐藏进度条 */
            width: 100%;
            background-color: #e0e0e0;
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            height: 10px;
            margin-bottom: 20px;
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        #progress-indicator {
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        #question-text {
          font-size: 18px;
          font-weight: 500;
          line-height: 1.6;
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        .option-item {
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          border: 1px solid #dee2e6;
          border-radius: 8px;
          padding: 15px;
          margin-bottom: 12px;
          cursor: pointer;
          transition: background-color 0.2s ease, border-color 0.2s ease;
        }

        .option-item:hover {
          background-color: #e9ecef;
        }
        
        .option-item.selected {
            background-color: #d1e7fd;
            border-color: #4a90e2;
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        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
          font-weight: 500;
          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
          box-shadow: 0 4px 12px rgba(0,0,0,0.15);
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        #next-btn {
            background-color: #28a745;
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        .nav-btn:hover {
          background-color: #357abd;
          transform: scale(1.05);
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        .nav-btn:disabled {
            background-color: #a0c3e8;
            cursor: not-allowed;
            opacity: 0.7;
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        #result-container {
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        .result-box {
            border-radius: 8px;
            padding: 20px;
            margin-top: 20px;
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        .result-box.correct {
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            border: 1px solid #c3e6cb;
            color: #155724;
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        .result-box.incorrect {
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            color: #721c24;
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        .result-box h3 {
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        .explanation-text {
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            line-height: 1.7;
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        .source-text {
            font-style: italic;
            font-size: 14px;
            margin-top: 15px;
            color: #555;
        }

        
        .final-score-container {
            padding: 40px;
            text-align: center;
        }
        .final-score-container h2 {
            margin-top: 0;
            margin-bottom: 30px;
        }
        .score-summary {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-bottom: 40px;
            flex-wrap: wrap;
        }
        .score-card {
            background-color: #f8f9fa;
            border-radius: 12px;
            padding: 20px;
            width: 180px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
            border: 1px solid #e9ecef;
        }
        .score-card h3 {
            margin: 0 0 10px;
            font-size: 16px;
            font-weight: 500;
            color: #555;
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        .score-card p {
            margin: 0;
            font-size: 28px;
            font-weight: 700;
            color: #333;
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        .score-details table {
            width: 100%;
            font-size: 16px;
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        .score-details td {
            padding: 4px 0;
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        .score-details td:last-child {
            text-align: right;
            font-weight: 700;
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        .report-actions button {
            background-color: #fff;
            border: 1px solid #ccc;
            border-radius: 8px;
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            font-size: 16px;
            cursor: pointer;
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            transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
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        .report-actions button:hover {
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        .hint-container {
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            border: 1px solid #b2ebf2;
            border-radius: 8px;
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            margin-top: 20px;
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            font-size: 15px;
            line-height: 1.6;
            display: none; /* 默认隐藏 */
        }
      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>大规模文件存储优化 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "当一个应用需要存储大量用户上传的非结构化数据（如图片、视频）时，根据文档，哪种存储系统因其高可扩展性而最为适用？",
    "options": [
      "块存储 (Block Storage)，因为它提供低延迟访问。",
      "分布式文件存储 (Distributed File Storage)，因为它专为大数据计算设计。",
      "对象存储 (Object Storage)，因为它适用于非结构化数据且具有高可扩展性。",
      "关系型数据库，因为它能有效管理文件元数据。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档明确指出，对象存储（如阿里云 OSS、Amazon S3）适用于非结构化数据存储，并提供高可扩展性，这使其成为存储海量图片和视频等文件的理想选择。块存储主要用于数据库等低延迟场景，而分布式文件存储更偏向于Hadoop等大数据计算环境。",
    "source": "文档中「2.1 选择合适的存储系统」部分",
    "hint": "思考一下，像S3或OSS这样的云服务通常被归类为什么存储类型？它们最擅长处理哪种数据？"
  },
  {
    "question": "为了在保证数据可用性的同时最大限度地优化存储成本，文档推荐了哪种核心策略来管理不同访问频率的数据？",
    "options": [
      "数据冷热分层存储",
      "小文件合并存储",
      "对所有数据进行压缩",
      "使用跨区域复制"
    ],
    "correctAnswerIndex": 0,
    "explanation": "数据冷热分层存储是关键的成本优化策略。它根据数据的访问频率（热、温、冷）将其存放在不同成本和性能的存储介质中（如SSD、HDD、归档存储），从而在满足业务需求的同时显著降低总存储成本。",
    "source": "文档中「2.3 数据冷热分层存储」部分",
    "hint": "文档中有一个表格，根据“访问频率”将数据分为了几种类型，并推荐了不同的存储方式。"
  },
  {
    "question": "在上传一个体积非常巨大的文件（例如超过1GB）时，为了提高上传速度和稳定性，应该采用文档中提到的哪种技术？",
    "options": [
      "使用预签名URL进行上传",
      "分片上传 (Multipart Upload)",
      "将文件存储在块存储中再迁移",
      "单线程顺序上传"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档在“分片存储策略”一节中特别强调，对于超大文件，应使用分片上传（Multipart Upload）。该技术将文件拆分成多个小块并行上传，不仅能显著提高上传速度，还能在部分分片上传失败时仅重传失败的部分，增强了可靠性。",
    "source": "文档中「2.2 分片存储策略」部分",
    "hint": "文档中提到了一个针对超大文件的性能提升方法，它将大任务分解为多个小任务并行处理。"
  },
  {
    "question": "对于一个存储了大量小文件的系统，文档指出其主要的成本瓶颈在于什么？并推荐了何种解决方案？",
    "options": [
      "存储空间占用过高；解决方案是启用数据压缩。",
      "API请求次数过多导致成本高昂；解决方案是合并存储。",
      "数据传输带宽不足；解决方案是使用CDN加速。",
      "备份恢复时间过长；解决方案是创建快照。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确指出，“存储大量小文件会占用大量存储请求（API 调用成本高）”。因此，核心成本问题在于请求次数。推荐的解决方案是“合并存储”，例如将多个小文件压缩成一个大包或建立索引文件，从而将多次API调用合并为少数几次。",
    "source": "文档中「4.2 小文件合并存储」部分",
    "hint": "思考一下对象存储的计费模式，除了存储容量，还有哪个因素会影响成本？"
  },
  {
    "question": "一个应用需要为用户提供一个临时的、安全的私有文件下载链接，同时不希望服务器直接参与数据传输以减轻负载。文档推荐使用哪种机制？",
    "options": [
      "基于IAM角色的精细化授权",
      "将存储桶(Bucket)权限设置为公共读",
      "使用CDN并配置缓存策略",
      "生成一个有时效性的预签名URL (Pre-signed URL)"
    ],
    "correctAnswerIndex": 3,
    "explanation": "预签名URL是为私有文件提供临时、安全访问权限的理想方式。服务端生成一个带有签名和过期时间的URL，客户端可直接使用此URL从对象存储下载文件，整个过程无需服务器中转，有效降低了服务器开销和权限管理的复杂性。",
    "source": "文档中「3.2 预签名 URL 提升访问性能」部分",
    "hint": "文档中提供了一段Java代码示例，用于生成一个具有一小时有效期的文件访问链接。"
  },
  {
    "question": "为了实现数据的自动化成本管理，例如“文件上传30天后自动转为低频存储，180天后自动删除”，应该配置什么功能？",
    "options": [
      "数据冗余备份策略",
      "存储生命周期策略",
      "Bucket访问权限策略",
      "跨区域复制规则"
    ],
    "correctAnswerIndex": 1,
    "explanation": "存储生命周期策略专门用于自动化管理对象的生命周期。通过配置规则，可以定义对象在创建后的一段时间自动转换到更便宜的存储类别（如标准转低频、低频转归档），或在到期后自动删除，是实现无人值守成本优化的关键功能。",
    "source": "文档中「4.1 使用存储生命周期策略」部分",
    "hint": "文档中有一段XML配置示例，展示了如何设置规则，让文件在不同天数后改变其`StorageClass`或触发`Expiration`。"
  },
  {
    "question": "为了应对区域性灾难（如整个数据中心故障）并确保数据的最高容灾能力，文档推荐了哪种数据备份策略？",
    "options": [
      "多AZ（可用区）存储",
      "开启版本控制功能",
      "跨区域复制 (Cross-Region Replication)",
      "对数据进行加密存储"
    ],
    "correctAnswerIndex": 2,
    "explanation": "多AZ存储可以抵御单个或多个可用区（同一区域内的数据中心）的故障，但无法抵御整个区域的灾难。跨区域复制（Cross-Region Replication）通过将数据异步复制到另一个地理位置遥远的区域，为数据提供了最高级别的容灾保障。",
    "source": "文档中「5.2 数据冗余备份」部分",
    "hint": "在数据冗余备份策略中，哪一项能够“提高数据容灾能力”以应对最大范围的故障？"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

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          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
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            showFinalScore();
            return;
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            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
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            optionsListEl.appendChild(li);
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          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
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            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
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            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

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                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  